Composition for controlling pitch in paper manufacture

ABSTRACT

Compositions containing one or more cationically charged aluminas and one or more sequestering agents for the sequestering of metal ions such as calcium, magnesium and iron are disclosed. Suitable sequestering agents include organo-phosphorus sequestering agents and also sodium glucoheptonate and its derivatives. These compositions are particularly effective in the control of pitch which forms during the manufacture of paper.

Carstens et a1.

COMPOSITION FOR CONTROLLING PITCH IN PAPER MANUFACTURE 175] Inventors: Ronald A. Carstens, Anucortes; William J. Butcher, Vancouver, both of Wash.

[73] Assignee: Key Chemicals, Inc., Anacortes,

Wash.

[22] Filed: Sept. 7, 1972 [21] Appl. No: 286,975

152] US. Cl 252/310; 162/181 B; 162/D1G. 4;

252/181; 252/313 R; 252/352; 252/D1G. 11

[51] Int. Cl B0lj 13/00 [58] Field of Search. 252/310, 313 R, 352, DIG. 11,

252/D1G. 17, 181; 162/181 B, DIG. 4

[56] References Cited UNITED STATES PATENTS 2.590.833 4/1952 Bechtold et a1. 252/313 R July 22, 1975 2.871.095 1/1959 Hervert et 252/313 R X 3.234.124 2/1966 Primary ExaminerRichard D. Lovering Attorney, Agent, or FirmHolman & Stern [57] ABSTRACT 8 Claims, No Drawings COMPOSITION FOR CONTROLLING PITCH IN PAPER MANUFACTURE BACKGROUND AND SUMMARY OF THE INVENTION The present invention is concerned with compositions for pitch control in the manufacture of paper. More particularly, the present invention is directed to compositions containing mixtures of cationically charged aluminas and sequestering agents which act to control the accumulation of pitch during the manufacture of paper.

in conventional processes for the manufacture of paper, there is formed a pitch component which interferes with the equipment employed in the paper making process. This pitch component appears to be formed in either of two basic ways.

Thus, the pitch particles which exist in paper pulp may come free from the fiber and form a negatively charged colloidal dispersion. When these particles are subjected to shear, as at certain points during the paper-making process, the charge of the particles decreases due to electrophoretic mobility causing the particle charges to collapse and initiating agglomeration of the pitch particles. Pitch may also be formed due to the presence of rosin acids (including rosins such as those used to size and waterproof paper as a byproduct of the pulp cooking operation) which react with certain cations such as calcium, iron, copper, or magnesium, to form an insoluble pitch component.

Prior art methods of treatment of such pitch have primarily relied on dispersing the negatively charged pitch particles with negatively charged surfactants but these methods have not proven to be satisfactory. Aluminas have also been employed for pitch control but such materials have not been particularly effective. Thus, while these previous methods have been successful to a limited extent, no one method or combination of methods has proven to be entirely satisfactory in controlling pitch produced during the paper-making process.

By the present invention, there is provided a composition for the effective control of pitch produced during the manufacture of paper, such compositions including one or more cationically charged aluminas in combination with one or more sequestering agents. The sequestering agents which are employed include organophosphorus sequestering agents as well as sodium glucoheptonate sequestering agents. ln these compositions of the present invention, the aluminas generally constitute from about l to 25 weight percent of the total dispersion while the sequestering agents are present in amounts of from about 1 to 70 weight percent of the dispersion, with the balance of the dispersion including water and various adjuvants.

Conventional additives such as anti-foam agents, cationic or non-ionic surfactants, corrosion inhibitors, freeze-thaw stabilizers, and the like may be added in customary proportions. Since the aqueous colloidal dispersion carries a positive charge, the use of anionic surfactants is generally to be avoided as such additives tend to result in poor or broken dispersions.

ln general, the components of the instant compositions are employed in a ratio of alumina to sequestering agent of about 0.1 to 8, preferably about 0.3 to l. A remarkable feature of the compositions of the present invention is the synergistic effect which is achieved by combining one or more of the aluminas with one or more of the sequestering agents.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The alumina components which are employed in the present invention are positively charged colloidal aqueous dispersions of aluminas having a particle size of about 4 to 100 millimicrons, a surface area of from about 100 to 300 square meters per gram and a purity in the range of at least about 97 to 99 percent dry weight alumina.

When more than one alumina composition is employed, it is preferred that the mixture of aluminas comprise about 25 to percent by weight of a first alumina composition having a particle size of about 4 6 ma, a surface area of about 300 m /gm, and a purity of at least about 99 percent dry weight alumina, with a second alumina composition having a particle size of about 20 30 mu, a surface area of about m /gm, and a purity of at least about 97 percent dry weight alumina. The alumina dispersion is prepared by adding 1 to 15 percent, preferably 3 to 6 percent and especially about 4 percent, of the alumina mixture to an acidified aqueous system having a pH of 0 to 6, preferably 3 to 4.

An important feature of the instant invention, in the case where more than one alumina composition is employed, resides in the mixture of aluminas having vastly different ultimate dispersed particle sizes, that is, at least one of the aluminas having an ultimate dispersed particle size no more than about one-fifth of the other, with about a 25 75 percent ratio of the first alumina being present in the mixture. The individual particle sizes, specific surface areas, purities, percent total solids content in the dispersion, and pH of the dispersion as discussed above and hereinafter provide optimum properties, but it is the use of a mixed particle size that provides unexpected results.

The alumina composition may be of any form, and, specifically, either an alpha, gamma or delta alumina may be employed with good results. where a mixture of aluminas is employed, alpha alumina compositions are preferably used as the first alumina component and such materials are commercially available. For example, the alumina identified as DISPAL M is quite satisfactory. DISPAL M has an average particle size of 4.8 mph, a surface area of 320 m /gm and a purity of 99 percent dry weight alumina. The first alumina should preferably have an ultimate dispersed particle size (the particle sizes are always referred to herein in a dispersion since upon drying these materials tend to agglomerate) of about 2 to 10 my. diameter, or even about 4 to 6 mp. The second alumina component may be of any form but preferably is of other than the alpha form. Particularly suitable are gamma and delta fumed aluminas. Commercially available aluminas identified as ALON C (gamma) and Aluminum Oxide C (delta) are quite suitable and particle sizes of about 10 to 100 mu diameter, preferably of about 20 to 30 mp, are often employed. ALON C has an average particle size of 30 mu, a surface area of 100 m /gm and a purity of 99 percent dry weight alumina while Aluminum Oxide c has an average particle size of 20 mu, a surface area of 100 m /gm and a purity of 97 percent dry weight alumina.

The two aluminas are admixed in a ratio of 25 to 75 percent by weight of the first alumina with correspondingly 75 to 25 percent by weight of the second alumina. Optimal proportions can readily be determined for particular application, but will generally contain from 35 to 65 percent by weight of each alumina. Particularly good results for many applications are obtained with 50 50 mixtures. The greater electrostatic charge resulting from the admixture of small and large alumina particles will necessarily be somewhat different for different ratios and the optimum effect will have to be determined for each application. Close packing or loose packing of such minute particles of greatly varying shapes may result in varying electrostatic charge.

The colloidal aqueous dispersions of the aluminas are prepared by standard methods, generally to a stock mixture having a solids content of about to 40 percent by weight which may be diluted with water to a solids content of about 1 to percent by weight. preferably about 4 to 9 percent, for subsequent use or the alumina powders may be added to acidified water having a pH of about 2 to 6, preferably about 3 to 4, and agitated. Suitable acids include hydrochloric acid, acetic acid, monochloroacetic acid, nitric acid, hydroxyacetic acid, sulfamic acid and the like; halogenated acids are preferred as they tend to result in more stable dispersions. Concentrated stock dispersions may be diluted with water or acidified water for subsequent use.

The sequestering agents which may be employed in the compositions of the present invention may be any of the organic phosphorus sequestering agents which have been found to be useful in sequestering metal ions such as calcium, magnesium. iron, zinc. copper and other metals. Thus, the phosphorus component may be a compound of the structure wherein R is an alkyl radical having from 1 to 5 carbon atoms, as well as alkali metal. ammonium and ethanolamine salts of said compound, and monoand dialkyl esters thereof, with the esterifying alcohol being methanol, ethanol, propanol or butanol. Such phosphorus compounds may be prepared by reacting phosphorous acid with acid anhydrides and/or acid chlorides. The preparation of these compounds is described in US. Pat. No. 3,214,454. A commercial phosphorus agent having the tradename DEQUEST 2000. 2006 or l0 may be employed as this component of the invention, these DEQUEST formulations corresponding to salts of hydroxyethylidene -l, l-diphosphonie acid. Additional phosphorus sequestering agents which may be employed include salts of polymethylenediamine tetra methyl phosphonic acids such as those acids having the formula wherein n equals 2 through 6. A commercial phosphonic acid known as DEQUEST 2041 or 205] is satis factory for use in the present invention. with the value of n in the previous formula being equal to 2 for DE QUEST 204] and being equal to 6 for DEQUEST 2051. The organophosphorus sequestering agents are often employed in aqueous solutions containing about 40 to 60 weight percent of solids.

Other sequestering agents which may be employed include sodium glucoheptonate syrup, which is the product obtained by adding to an aqueous solution of corn syrup the quantity of sodium cyanide stoichiometrically equivalent to the dextrose and disaccharide content of the corn syrup. The term sodium glucoheptonate syrup" as used herein is intended to include the sodium glucoheptonates formed in such reactions and also the sodium salts of the sugar acids derived from the aldoses and disaccharides which are present in the corn syrup. Preparation of sodium glucoheptonate syrup is described in U.S. Pat. No. 3,022,343. A commercial sodium glucoheptonate syrup known as SEQLENE may be employed in the dispersions of the present invention with good results. The sodium glucoheptonate syrup may be employed in these dispersions in amounts of about 1 to 20 weight percent of the total dispersion. The syrup is often employed in an aqueous solution containing about 35 to weight percent of solids.

The phosphorus sequestering agents are generally employed in amounts of about 1 to 50 percent by weight of the total dispersion and one or more such phosphorus components may be employed up to this amount with good results. Where the sodium glucoheptonate syrup is employed as an additional sequestering agent, this component is usually employed in amounts of from about l to 20 percent by weight of the total dispersion, in addition to from about i to 50 percent by weight of the phosphorus component. The remainder of the dispersion is then made up of the alumina component and water along with various adjuvants.

The method of mixing the various components to prepare the compositions of the present invention may be by any conventional method and the order of addition and the temperature employed are not critical. Thus, for example, the sequestering agent may be added to the alumina dispersion and the water and adjuvants then combined with the resulting dispersion. The pH of the final dispersion should be adjusted to a value of about 4.5 to 6 preferably about 5.

The following example provides an embodiment of the method of pitch control employing a composition of the present invention. The composition had the following formulation:

A nonionic polyoxyeihylcne surfactant "A polymeric dispersant A protective protein colloid A kJllUnlC bactcricidc A number three paper machine having a plastic foil forming surface and a plastic wire on a standard Fourdriner paper machine was employed in the manufacture of Moore business grade paper. Due to severity of pitch formation on the foils, forming board and wires, it was impossible to make this paper. As soon as the equipment was started up, it became plugged and a shut-down for cleaning was necessary. This procedure was repeated several times with the same result. Following this procedure in which no paper could be manufactured, the composition of the present invention having the formulation as shown in Table I was added to the paper dispersion in the amount of 2.86 pounds per ton of stock and the same machine was then employed in the manufacture of Moore business grade paper, this time with a highly successful operation. During this period, there was no downtime experienced due to pitch accumulation and only trace amounts of pitch were observed in the system.

In an additional run in which the composition of the present invention was not employed, Moore business grade paper was again attempted to be produced and it was necessary to shut the machine down within approximately two to three hours after commencement of operation in order to clean pitch from the machine. By the addition of the composition of the present invention in the amount of 2.86 pounds per ton of stock, Moore business grade paper was produced throughout the operating period until the end of the order without any pitch accumulation to interfere with production.

As can be seen from the above examples of the operation of paper making equipment in which the composition of the present invention is employed, even during conditions of most severe pitch accumulation, the composition of the present invention was capable of reducing the amount of pitch in the system in order to allow the production of high quality paper.

lt is claimed:

1. A colloidal aqueous dispersion for control of pitch in a paper pulp system which consists essentially of:

a. about 1 to 25 weight percent of an alumina component;

b. about 1 to 50 weight percent of an organophosphorus sequestering agent selected from the group consisting of: a compound having the structure wherein R is an alkyl radical having from 1 to 5 carbon atoms; alkali metal, ammonium and ethanolamine salts of said compound, monoand dialkyl esters of said compound with methanol, ethanol, propanol or butanol', and a salt of polymethylenediamine tetramethyl phosphonic acid having the formula wherein n equals 2 through 6; and

c. sodium glucoheptonate syrup in an amount of about I to weight percent of the total dispersion. 2. A colloidal aqueous dispersion for control of pitch in a paper pulp system which consists essentially of:

a. about I to weight percent of an alumina component; b. about I to 50 weight percent of a mixture of phosphorus compositions, one of which is a sequestering agent selected from the group consisting of: a compound having the structure O R 0 ll I ll HO P C P OH I l I OH OH OH wherein R is an alkyl radical having from 1 to 5 carbon atoms; alkali metal, ammonium and ethanolamine salts of said compound, monoand dialkyl esters of said compound with methanol, ethanol, propanol, propanol or butanol; and a salt of polymethylenediamine tetramethyl phosphonic acid having the formula wherein n equals 2 through 6; and

c. sodium glucoheptonate syrup in an amount of about 1 to 20 weight percent of the total dispersion.

3. The dispersion of claim 2 wherein the alumina component comprises 25 to percent by weight of a first alumina composition having an ultimate dispersed particle size no more than about one-fifth as great as a second alumina composition and correspondingly 75 to 25 percent by weight of said second alumina composition.

4. A colloidal aqueous dispersion for control of pitch in a paper pulp system which consists essentially of:

a. about 1 to 25 weight percent of an alumina component comprising 25 to 75 percent by weight of a first alumina composition having an ultimate dispersed particle size no more than about one-fifth as great as a second alumina composition and correspondingly 75 to 25 percent by weight of said second alumina composition; and

b. about 1 to 50 weight percent of an organophosphorus sequestering agent selected from the group consisting of: a compound having the structure O R 0 II I ll HO r C ll OH OH OH OH wherein R is an alkyl radical having from 1 to 5 carbon atoms; alkali metal, ammonium and ethanolamine salts of said compound, monoand dialkyl esters of said compound with methanol, ethanol, propanol or butanol; and a salt of polymethylenediamine tetramethyl phosphonic acid having the formula wherein n equals 2 through 6.

5. The dispersion of claim 4 wherein said first alumina composition has a particle size of about 2 to 10 my. and said second alumina composition has a particle size of about 10 to mu.

6. The dispersion of claim 5 wherein said first alumina composition has a particle size of about 4 to 6 mp. and said second alumina composition has a particle size of about 20 to 30 mu.

7. The dispersion of claim 4 wherein said first alumina composition comprises an alpha alumina and said second alumina composition comprises a gamma or delta alumina.

8. A colloidal aqueous dispersion for control of pitch in a paper pulp system which consists essentially of:

0 R 0 ll l ll HO P c P OH OH OH OH wherein R is an alkyl radical having from 1 to 5 carbon atoms; alkali metal, ammonium and ethanolamine salts of said compound, monoand dialkyl esters of said compound with methanol, ethanol, propanol or butanol; and a salt of polymethylenediamine tetramethyl phosphonic acid having the formula wherein n equals 2 through 6. 

1. A COLLOIDAL AQUEOUS DISPERSION FOR CONTROL OF PITCH IN A PAPER PULP SYSTEM WHICH CONSISTS ESSENTIALLY OF: A. ABOUT 1 TO 25 WEIGHT PERCENT OF AN ALUMINA COMPONENT, B. ABOUT 1 TO 50 WEIGHT PERCENT OF AN ORGANO-PHOSPHOROUS SEQUESTERING AGENT SELECTED FROM THE GROUP CONSISTING OF: A COMPOUND HAVING THE STRUCTURE
 2. A colloidal aqueous dispersion for control of pitch in a paper pulp system which consists essentially of: a. about 1 to 25 weight percent of an alumina component; b. about 1 to 50 weight percent of a mixture of phosphorus compositions, one of which is a sequestering agent selected from the group consisting of: a compound having the structure
 3. The dispersion of claim 2 wherein the alumina component comprises 25 to 75 percent by weight of a first alumina composition having an ultimate dispersed particle size no more than about one-fifth as great as a second alumina composition and correspondingly 75 to 25 percent by weight of said second alumina composition.
 4. A COLLOIDAL AQUEOUS DISPERSION FOR CONTROL OF PITCH IN A PAPER PULP SYSTEM WHICH CONSISTS ESSENTIALLY OF: A. ABOUT 1 TO 25 WEIGHT PERCENT OF AN ALUMINA COMPONENT COMPRISING 25 TO 75 PERCENT BY WEIGHT OF A FIRST ALUMINA COMPOSITION HAVING AN ULTIMATE DISPERSED PARTICLE SIZE NO MORE THAN ABOUT ONE-FIFTH AS GREAT AS A SECOND ALUMINA COMPOSITION AND CORRESPONDINGLY 75 TO 25 PERCENT BY WEIGHT OF SAID SECOND ALUMINA COMPOSITION, AND B. ABOUT 1 TO 50 WEIGHT PERCENT OF AN ORGANO-PHOSPHORUS SEQUESTERING AGENT SELECTED FROM THE GROUP CONSISTING OF: A COMPOUND HAVING THE STRUCTURE
 5. The dispersion of claim 4 wherein said first alumina composition has a particle size of about 2 to 10 m Mu and said second alumina composition has a particle size of about 10 to 100 m Mu .
 6. The dispersion of claim 5 wherein said first alumina composition has a particle size of about 4 to 6 m Mu and said second alumina composition has a particle size of about 20 to 30 m Mu .
 7. The dispersion of claim 4 wherein said first alumina composition comprises an alpha alumina and said second alumina composition comprises a gamma or delta alumina.
 8. A colloidal aqueous dispersion for control of pitch in a paper pulp system which consists essentially of: a. about 1 to 25 weight percent of an alumina component comprising 25 to 75 percent by weight of a first alumina composition having an ultimate dispersed particle size no more than about one-fifth as great as a second alumina composition and correspondingly 75 to 25 percent by weight of said second alumina composition; and b. about 1 to 50 weight percent of a mixture of phosphorus compositions, one of which is a sequestering agent selected from the group consisting of: a compound having the structure 